A photosensor utilizing an amplifying function of a MOS transistor, called a CMOS sensor, can be manufactured by a general CMOS process. Thus, manufacturing cost of a solid-state imaging device including a CMOS sensor in each pixel can be low, and a semiconductor device having a photosensor and a display element formed over one substrate can be realized. In addition, a CMOS sensor requires lower driving voltage than a CCD sensor; therefore, power consumption of the solid-state imaging device can be suppressed.
A solid-state imaging device including a CMOS sensor generally employs, for imaging, a rolling shutter method in which an operation to accumulate charge in a photodiode and an operation to read the charge are sequentially performed row by row (see Patent Document 1). In some cases, such a solid-state imaging device employs a global shutter method in which all the pixels are subjected to an operation to accumulate charge at a time, instead of the rolling shutter method.